this is where I came in

1. This is where I began, my knowledge dates from this point. For example, Do you have anything more to add, because if not, this is where I came in. This idiom, dating from the 1920s, originally alluded to the continuous showing of a motion picture, with customers entering the theater at any stage while the film was running and leaving when it reached the point where they had started.

Example Sentences

He continued his anti-Trump comments, "This is where I came in, and I saw that they edited all that."

From Salon

“I’m reliving a part of history I had no desire to live again. And I hoped I wouldn’t. And by the way, that makes it easier to leave — this is where I came in,” Ellsberg said in a video interview, his voice increasingly raspy as he spoke surrounded by books in his California home.

From Washington Post

In an essay on Edward Hopper, “The Nothing That Is Not There,” Leonard Michaels writes: “It wasn’t important, in Hopper’s day, to see a movie from the beginning. People often arrived in the middle, which led to an expression we no longer hear, ‘This is where I came in.’

From New York Times

This is where I came in, serving as editor and linguist consultant for the project, a monumental collaborative effort involving thousands of hours of translating, editing, recording and photographing.

From Time

It was a time for Velasco to say: "This is where I came in;" an army coup had chucked him out of the Ecuadorian presidency in 1935, a revolution had brought him back from Colombian exile nine years later to make him President again.

From Time Magazine Archive